Separation method for a mixture comprising a solvent and c4 or higher linear alpha olefins, and method and device for preparing ethylene oligomer utilizing the separation method

Abstract

The present invention relates to a separation method for a mixture comprising a solvent and C4 or higher linear alpha olefins, and method and device for preparing ethylene oligomer utilizing the separation method, and more specifically, a method capable of separating a mixture, which was generated after oligomerization reaction of ethylene and comprises a solvent and C4 or higher linear alpha olefins, into the solvent, C6 or lower linear alpha olefin, and C8 or higher linear alpha olefin even by one-time treatment, and a method and a device for preparing ethylene oligomer utilizing the separation method.

What is claimed is: 
     
         1 . A method for separating a mixture comprising a solvent and C4 or higher linear alpha olefins, the method comprising:
 distilling a mixture comprising a solvent having a boiling point higher than C6 linear alpha olefin and lower than C8 linear alpha olefin, C6 or lower linear alpha olefin, and C8 or higher linear alpha olefin in a dividing wall column, to discharge the C6 or lower linear alpha olefin from the overhead of the dividing wall column, discharge the solvent from the first side of the dividing wall column, and discharge the C8 or higher linear alpha olefin from the bottom or a lower side than the first side of the dividing wall column.   
     
     
         2 . The method of  claim 1 , wherein the solvent having a boiling point higher than C6 linear alpha olefin and lower than C8 linear alpha olefin is selected from the group consisting of benzene, toluene, xylene, chlorobenzene, dichlorobenzene, pentane, hexane, heptane, methylcyclohexane, cyclohexane and combinations thereof. 
     
     
         3 . The method of  claim 1 , wherein the mixture comprises, based on total 100% by weight of the mixture, 50 to 95% by weight of the solvent having a boiling point higher than C6 linear alpha olefin and lower than C8 linear alpha olefin, 0.5 to 10% by weight of the C6 or lower linear alpha olefin, and 4 to 40% by weight of the C8 or higher linear alpha olefin. 
     
     
         4 . The method of  claim 1 , wherein the distillation in the dividing wall column is conducted at a temperature of 50° C. to 250° C. and under a pressure of 0.2 bar to 15 bar. 
     
     
         5 . The method of  claim 1 , wherein each of the C6 or lower linear alpha olefin and C8 or higher linear alpha olefin discharged from the dividing wall column is distilled additionally. 
     
     
         6 . A method for preparing ethylene oligomer, the method comprising the steps of:
 (1) conducting ethylene oligomerization reaction in a solvent having a boiling point higher than C6 linear alpha olefin and lower than C8 linear alpha olefin;   (2) removing unreacted ethylene from the resulting reaction mixture of step (1); and   (3) distilling the resulting mixture after the removal of unreacted ethylene in step (2) in a dividing wall column, to discharge C6 or lower linear alpha olefin from the overhead of the dividing wall column, discharge the solvent from the first side of the dividing wall column, and discharge C8 or higher linear alpha olefin from the bottom or a lower side than the first side of the dividing wall column.   
     
     
         7 . The method of  claim 6 , wherein the solvent having a boiling point higher than C6 linear alpha olefin and lower than C8 linear alpha olefin is selected from the group consisting of benzene, toluene, xylene, chlorobenzene, dichlorobenzene, pentane, hexane, heptane, methylcyclohexane, cyclohexane and combinations thereof. 
     
     
         8 . The method of  claim 6 , wherein the unreacted ethylene removed in step (2) is recovered for reuse in the oligomerization reaction of ethylene in step (1). 
     
     
         9 . The method of  claim 6 , wherein heat is transferred from the resulting mixture after the removal of unreacted ethylene in step (2) to the resulting reaction mixture of step (1). 
     
     
         10 . The method of  claim 6 , wherein the mixture distilled in the dividing wall column in step (3) comprises, based on total 100% by weight of the mixture, 50 to 95% by weight of the solvent having a boiling point higher than C6 linear alpha olefin and lower than C8 linear alpha olefin, 0.5 to 10% by weight of the C6 or lower linear alpha olefin, and 4 to 40% by weight of the C8 or higher linear alpha olefin. 
     
     
         11 . The method of  claim 6 , wherein the distillation in the dividing wall column in step (3) is conducted at a temperature of 50° C. to 250° C. and under a pressure of 0.2 bar to 15 bar. 
     
     
         12 . The method of  claim 6 , wherein the solvent discharged from the dividing wall column in step (3) is recovered for reuse in the oligomerization reaction of ethylene in step (1). 
     
     
         13 . The method of  claim 6 , wherein each of the C6 or lower linear alpha olefin and C8 or higher linear alpha olefin discharged from the dividing wall column in step (3) is distilled additionally. 
     
     
         14 . The method of  claim 13 , wherein heat is transferred from the fractional distillation product of C8 or higher linear alpha olefin to the fractional distillation product of C6 or lower linear alpha olefin. 
     
     
         15 . A device for preparing ethylene oligomer, the device comprising:
 (a) an ethylene oligomerization reactor;   (b) a first distillation column in fluid communication with the bottom of the ethylene oligomerization reactor; and   (c) a dividing wall column in fluid communication with the bottom of the first distillation column,   wherein the device is operated in a manner that:   in the ethylene oligomerization reactor, ethylene oligomerization reaction is conducted in a solvent having a boiling point higher than C6 linear alpha olefin and lower than C8 linear alpha olefin,   the resulting mixture of the ethylene oligomerization reaction is discharged from the bottom of the ethylene oligomerization reactor, and it is then fed into the first distillation column and distilled therein,   as a result of the distillation in the first distillation column, a mixture comprising the solvent and C4 or higher linear alpha olefins is discharged from the bottom of the first distillation column, and it is then fed into the dividing wall column and distilled therein, and   as a result of the distillation in the dividing wall column, C6 or lower linear alpha olefin is discharged from the overhead of the dividing wall column, the solvent is discharged from the first side of the dividing wall column, and C8 or higher linear alpha olefin is discharged from the bottom or a lower side than the first side of the dividing wall column.   
     
     
         16 . The device of  claim 15 , further comprising an ethylene recovery line fluidly communicating the first distillation column and the ethylene oligomerization reactor. 
     
     
         17 . The device of  claim 15 , further comprising a means for heat transfer from the bottom effluent of the first distillation column to the bottom effluent of the ethylene oligomerization reactor. 
     
     
         18 . The device of  claim 15 , further comprising a solvent recovery line fluidly communicating the dividing wall column and the ethylene oligomerization reactor. 
     
     
         19 . The device of  claim 15 , further comprising a device for distilling C6 or lower linear alpha olefin which is in fluid communication with the overhead of the first distillation column; and a device for distilling C8 or higher linear alpha olefin which is in fluid communication with the bottom or a lower side than the first side of the dividing wall column. 
     
     
         20 . The device of  claim 19 , further comprising a means for heat transfer from the fractional distillation product of C8 or higher linear alpha olefin to the fractional distillation product of C6 or lower linear alpha olefin.